Registry changed desktop

My computer had locked up so I shut off power and restarted it. When it came back up it had a window that said 'had to read from alt registry' with an ok button. When I clicked to my destop, it came up as a new user desktop.
I had forgot that my system restore was turned off from a previous action to rid a virus and I had forgot to turn it back on. I did now but can't go back to a restore point for that reason I assume. I did have it on a few months back but it won't let me go to that either. I don't have the registry backed up either but will now. Is there any way I can easliy correct the registry that it was trying on bootup and couldn't? I'm running Windows XP SP2 on a Celeron
2.4 GHz CPU with 768 MB RAM.

 

It seems as though it automatically installed me as a new user with a new desktop. I notice a new folder in the user directories. I think System Restore is now enabled but just for the new users restore points of which there aren't except for today. That explains why System Restore wasn't enabled for me as a new user. I want to know how to fix and get back to my original user. Can anyone advise?